1. Field of the Invention
The present invention relates to the manipulation of fluid-driven artificial muscles for controlled actuation of elements. More specifically, the invention relates to apparatus and methods employing an artificial muscle to articulate the effective control of elements such as, for example, a fluid control surface of a vehicle.
2. Description of the Problem and Prior Art
Since the advent of vehicle flight, methods to obtain improved aerodynamic performance have been under consideration. The ability to maneuver a fixed wing aircraft is limited by factors related to airfoil design, weight, and flight conditions. However, vehicle performance and adaptability can be considerably increased through the implementation of control surface actuation. An actuation system appropriately placed can command authority over a vehicle's roll, pitch, or yaw. This capability in aircraft is one of the primary means of expanding the flight envelope, while maintaining vehicle stability and control.
Historically, control surfaces have primarily consisted of trailing edge flaps (ailerons), elevators, and rudders, where the ailerons control the rolling moment, the elevators control the pitching moment, and the rudder has control over the yaw moment. These control surfaces are typically actuated by hydraulic fluid systems or electric motors. Operating under high pressure, hydraulic systems are capable of producing large, sustainable control forces, but one noted disadvantage is the increase in weight resulting from the bulky actuator components, associated fluid, and piping. Electric motors are also capable of generating large control forces at high rates, but limitations are introduced by their size, power, and weight. Actuation methods that employ active material systems have proven to be limited in output performance for full-scale vehicles, even in the presence of mechanisms designed for mechanical advantage. The prior art actuation systems were all designed to accomplish essentially the same task. That is, to improve the aerodynamic performance of the host vehicle.